(1) Field of the Invention
The present invention relates generally to automatic watch winders for winding self-winding watches, and in particular to watch winders that impart a winding motion to watches in a manner similar to the motion imparted when the watch is worn.
(2) Description of the Prior Art
The winding mechanism of a self-winding watch is comprised of a ball bearing mounted pendulum or rotor that is connected through a gear reduction system to the mainspring of the watch. Generally, the rotor can rotate 360xc2x0 in either direction. However, there are also so-called xe2x80x9chammerxe2x80x9d shaped rotors in older self-winding watches that have a limited travel of 150xc2x0 to 220xc2x0 rotation. In either case when the watch is worn, the user""s random and often rapid arm movements cause the rotor to swing back and forth inertially in both directions around the rotor axis, thereby winding the watch spring. The watch spring generally stores sufficient energy to keep the watch operating 36-48 hours, whether worn or not. Thus, when worn daily, the watch will be sufficiently wound to maintain continuous operation. However, if the watch is not worn regularly, the user must wind the watch, either manually or with a watch winder, or the watch will stop.
Prior art watch winders are typically comprised of an electric drive mechanism that rotates a watch carrier adapted to hold a watch with the plane of the watch perpendicular to the axis of rotation. That is, the rotor axis is parallel to the axis of rotation of the drive mechanism, so that the watch rotates in the same plane as the hands of the watch. During the period of activation, the watch is completely rotated several times either in a clockwise or counter-clockwise direction or, alternately, reversing in both directions. During the 360xc2x0 rotation of the watch, the rotor hangs downward, so that the watch rotates while the rotor is essentially stationary and the winding action is totally caused by gravity operation. That is, the motion is essentially the opposite from the way in which the winding mechanism is designed, i.e., rotation of the rotor around the rotor axis caused by inertial movement resulting from the wearer""s random movements. As a result, the powered rotation of the watch must be controlled to limit the turns per day (TPD) to prevent damage or malfunction due to the forces exerted on the winding mechanism.
U.S. Pat. No. 6,254,270, issued Jul. 3, 2001, describes an alternative watch winder design in which a self-winding watch is mounted on a horizontal or inclined, e.g., 30xc2x0, shaft or spindle, with the watch band being positioned around the spindle so that the face of the watch is generally parallel to the axis of rotation, and moves along a circular pathway during rotation of the spindle. The orbital motion of the watch about the inclined axis causes the rotor to swing back and forth, or oscillate, thereby generally replicating the effect of a person""s natural arm movements. When a 30xc2x0 angle from horizontal is chosen, each rotation causes the rotary pendulum to move through an arc of 120xc2x0.
While this latter mechanism more closely simulates the natural forces to which the watch is subjected when worn, there is still a need for a device that will impart a greater oscillation to the rotor, more closely simulating the bi-directional random inertial movement to which an automatic watch is subjected when worn, and which will enable an automatic watch to be adequately wound in a shorter period of time without any concern for winding direction, and also requiring less energy.
The present invention is directed to a watch winder for winding automatic watches in a manner that closely approximates the way in which automatic watches are wound when worn. Moreover, the present invention permits winding of automatic watches rapidly regardless of the winding direction required by a particular watch, and with reduced energy requirements compared to prior art devices.
Generally, the present watch winder achieves these results by providing a watch carrier holding one or more watches having a horizontal or inclined axis of rotation with the center of gravity of the carrier being laterally offset in a given direction from the axis of rotation, and a drive mechanism to rotate the watch carrier around the axis until the given direction, or center of gravity, is in the uppermost position, whereupon the carrier is free to rotate about the axis under the influence of both gravity and inertial force, causing the carrier to oscillate around the axis bi-directionally for several excursions.
The watch or watches is supported on the watch carrier with the face of the watch being perpendicular to the axis of rotation of the carrier. That is, the axis of rotation of the watch pendulum or rotor is parallel to the axis of rotation of the carrier. As a result, the rapid oscillation of the watch carrier and the abrupt direction changes cause the rotor to spin about the rotor axis in much the same manner as the spinning that occurs when the watch is worn by a user. Moreover, since the rotor tends to spin entirely or largely around the rotor axis for several excursions, as opposed to only the single 120xc2x0 or so achieved with prior art devices, the watch is more rapidly wound, and less energy is required, prolonging battery and/or winder life.
More specifically, the powered drive mechanism used to rotate the carrier is comprised of a shaft rotated by electric motor that is connected to the shaft through a set of reduction gears. The shaft is preferably rotated at from about 10 to about 12 revolutions per hour (rph). Alternately, a control system can be programmed to provide a single revolution with a variable xe2x80x9csleepxe2x80x9d time between cycles (every 5 to 6 minutes). The shaft engages the watch carrier upon rotation and rotates the shaft until the center of gravity of the carrier reached the apex of rotation, i.e., until the direction of the center of gravity from the rotational axis extends vertically upward. For example, a torque arm may extend laterally from the shaft, with the outer end of arm moving along a circular pathway upon rotation of shaft to push against an element on the watch carrier. The same rotation action can also be generated by a stepper motor, rotary solenoid, bellcrank drive, or other rotary drive means.
The watch carrier includes a watch support to hold one or more watches with the watch face perpendicular to the axis of rotation of the carrier, thus aligning the rotor axis parallel to the axis of rotation of the carrier. The axis of rotation may extend through the center of the watch, as when the carrier is designed to only support one watch. Alternatively, if the carrier is designed to support a plurality of watches, the watches can be offset from the carrier axis. The watch carrier may include a watch support that is removably held within a recess in the carrier.
The element on the carrier that is engaged by the torque arm may be a projection that extends from the carrier into the pathway of the torque arm. The projection is offset from the carrier axis in the same direction as the center of gravity of the carrier. Preferably, the watch support positions the watch so that the watch is in an upright position, facilitating the viewing of the watch time, when center of gravity of the watch carrier is in a downward direction which is the normal rest position. The center of gravity can be offset from the carrier axis due to the design of the carrier, or by attaching a counterweight to one side of the carrier.
Different styles of automatic watches have different winding requirements, normally determined by the number of desired rotations of the rotor within a given time period, e.g., a twenty-four hour period. Therefore, the length of time that the watch winder is activated and the length of time between activations should be set to meet the specifications of the watch being wound. The present invention provides a controller for use in setting these parameters. Rotation direction may also be set by the controller but the inherent bi-directional oscillating action of the winder does not make this mandatory.
In addition, the controller can be used to deactivate the motor when the torque arm is at the apex of its pathway, thereby avoiding contact of the torque arm with the carrier during the carrier oscillation, and allowing the oscillations to stop before the arm again engages the carrier. The watch winder may be mounted in a case that can include a hinged lid to enclose the watch carrier. Control knobs or switches can be mounted on the case to adjust the controller.
In operation, the drive mechanism is periodically energized in accordance with the specifications of the watch to be wound. Rotation of the shaft causes the torque arm to push against a part of the carrier, rotating the carrier until the center of gravity of the carrier is above the shaft. For example, if the carrier includes a counterweight on one side, so that the weighted side is heavier, the shaft will rotate the carrier until the weighted side of the carrier is at the apex of the rotation. Upon reaching the apex, gravity causes the watch carrier to rotate at a speed greater than the speed of rotation of the shaft, disengaging the carrier from the torque arm.
The weighted side of the carrier is then carried past the bottom or lowest point of the pathway by its momentum to a point near the apex on the opposite side of the pathway, whereupon the direction of rotation of the watch carrier is reversed. The cycle is repeated through multiple oscillations of decreasing length until the carrier comes to rest with the weighted side of the carrier at the bottom position, or until the carrier is again engaged by the drive mechanism to return the weighted side of the carrier to the top of its circular pathway. If desired, the drive mechanism can be de-energized during oscillation of the carrier to prevent the drive mechanism from engaging the carrier during oscillation.
Oscillation of the watch carrier causes a corresponding oscillation of the watch rotor which spins rapidly around the rotor axis thereby winding the watch in a manner closely simulating the spinning of the rotor that occurs during normal winding of the watch when the watch is worn by a user. The time required to wind the watch, the need for bi-directional rotation, and the energy required, is also substantially reduced due to the greater rotation of the rotor.